OMRON MX2 frequency converter debugging

Braking resistor: connected to P/+and RB terminals. Built in brake chopper, b090 (brake utilization rate) and b095 (brake action selection) need to be set.

3.2 Control terminal wiring

The control terminal is located behind the front cover plate and uses pluggable terminals. The main signals include:

Terminal Function Description

P24 24V internal power supply 100mA, for logic input use

PLC input common terminal selects source or drain logic through short circuiting

1-7 intelligent inputs can be configured with over 50 functions (such as FW, RV, CF1, etc.)

11,12 open collector electrode output maximum 50mA/27V, can be configured with RUN, FA1, etc

AL0~AL2 relay output 1C contact, default alarm output

O. OI analog input 0~10V voltage or 4~20mA current, input impedance 10k Ω/100 Ω

AM analog output 0~10V, can monitor frequency, current, etc

EA, EB pulse input EA up to 32kHz, used for frequency setting or encoder feedback

SP, SN RS485 communication Modbus RTU, built-in 200 Ω terminal resistor (dip switch)

3.3 Source/Drain Switching

By changing the short-circuit position between PLC and P24, L:

Source type: Short circuit PLC and L, then connect P24 to the input terminal and turn it on.

Leakage type: Short circuit PLC and P24, then connect L to the input terminal and turn it on.

The factory default is the source type. The power must be turned off before changing the short-circuit.

Keyboard operation and basic parameter settings

MX2 comes standard with a 4-digit 7-segment LED keyboard with Run, Stop/Reset, directional keys, and setup keys. Monitor and set through parameter groups (D/F/A/B/C/H/P).

4.1 Inspection before power on test

Confirm that the short connector is not missing between+1 and P/+2.

Confirm that the motor is disconnected from the load.

Confirm that the power supply voltage is correct and the grounding is reliable.

4.2 Minimum necessary parameter settings

The following steps take keyboard control as an example:

Set frequency command source (A001): Set to 02 and select the digital operator (F001 set value).

Set the command source (A002) to 02 and select the RUN/STOP key on the keyboard.

Set the motor fundamental frequency (A003): Set it to 50.0 or 60.0Hz according to the motor nameplate.

Set motor voltage (A082): 230V for 200V level and 400V for 400V level.

Set motor current (b012): generally set as the percentage of the rated current of the motor divided by the rated current of the frequency converter, or directly input the current value (range 20%~100%).

Set the number of motor poles (H004): For common 4-pole motors, choose 4.

Acceleration and deceleration time (F002/F003): default 10 seconds, adjustable as needed.

After completing the above settings, press the RUN button and the motor should be able to start normally.

Common Function Parameter Analysis

5.1 Multi speed operation

By configuring the intelligent input terminals CF1~CF4 (corresponding to C001~C007 set as 02~05), 16 preset speeds (A020~A035) can be selected in combination. A019 is set to 00 as a binary combination and 01 as a bitwise operation.

5.2 PID Control

When enabling constant pressure/constant current control for water pumps, fans, etc., set A071 to 01 (enabled) and set:

A072: Proportional gain

A073: Integral time (Ti, set to 0 to disable integral)

A074: Differential time

A076: Feedback signal source (O voltage or OI current)

A075: Feedback range scaling.

The PID output can be limited to A078 (%) and excessive deviation can be monitored through the intelligent output terminal [OD].

5.3 DC braking

Used for quick shutdown or positioning. Set A051=01 (braking when stopped), A052 is the starting frequency of braking, A054 is the braking power (0~100%), and A055 is the braking time. For high inertia loads, it can be used in conjunction with external braking resistors.

5.4 Carrier frequency and derating

The adjustable range of b083 is 2.0~15kHz. High carrier frequency reduces motor noise, but increases frequency converter heating and leakage current. When the ambient temperature exceeds 40 ℃ or when installed side by side, the carrier frequency or output current must be reduced according to the derating curve in the manual.

Fault code analysis and troubleshooting

When the MX2 frequency converter malfunctions, the digital display shows E xxx and the ALARM light is on. The following are common faults and their solutions:

Common reasons and solutions for code names

E01 constant speed overcurrent output short circuit, motor jamming, excessive load check output cable and motor insulation to reduce load

E02 deceleration overcurrent, too short deceleration time, extended deceleration time (F003) or enabled overvoltage suppression (b130)

E03 Acceleration overcurrent, short acceleration time, high torque boost, extended acceleration time (F002), reduced manual torque boost (A042)

E05 motor overload: The motor has been overloaded for a long time and the electronic thermal protection is set improperly. Check the load and adjust b012 to the rated current of the motor

E06 brake resistor overload brake usage rate exceeds b090 set to reduce brake load or increase b090, check the brake resistor

E07 Excessive regenerative energy during overvoltage deceleration prolongs deceleration time, or external braking resistor is connected